This can be done, but only by people who have too WAY much free time on their
hands.
Label templates are not meant for manual typing of addresses, they are meant
to receive the output of a mailmerge. You type your addresses into a TABLE,
which can be in Word, Excel or a database such as Access, SQL Server, Oracle,
DB2, or any number of other db's which range from newbie-friendly to
industrial/military strength. In a table, it's easy to insert an entries
anywhere you want, or better yet, add them at the end and then sort the
table. After making the additions, you rerun the mailmerge to create the new
set of labels.
See Word help, and especially
http://www.word.mvps.org/ and search for Mail
Merge to get lots of info on how to get started.
--
Ted